This invention relates to the construction and repair of footwear and, more particularly, to an improved system for applying new soles and top lifts to shoes.
A number of machines have been proposed for the application of either soles or top lifts to shoes. However, such machines have generally been both bulky and expensive, and have required a substantial level of skill on the part of an operator. Shoe repair with the prior machines has thus involved substantial labor and capital costs, causing the cost of repairing a shoe to approach the purchase price of the shoe.
The following U.S. patents disclose shoe construction or repair machines having many of the characteristics described above: Pratt et al. U.S. Pat. No. 2,221,880; Hart, U.S. Pat. No. 2,619,661; Juhola et al. U.S. Pat. No. 2,766,467; and Morgan, U.S. Pat. No. 3,483,582. Each of the disclosed machines is a power operated machine of substantial complexity and cost. The machine of Hart U.S. Pat. No. 2,619,661 is a complex pneumatically operated press using high frequency electromagnetic radiation to activate a cement compound. Similarly, Juhola et al. U.S. Pat. No. 2,766,467 discloses a rather complex hydraulic press incorporating a magnetron oscillator for producing dielectric heat seam bonding of a shoe sole to a shoe.
Morgan U.S. Pat. No. 3,483,582 discloses a power operated mechanism for heating a shoe sole and the underside of a shoe, and thereafter applying the sole to the shoe. The sole is placed on the shoe at a first location and then moved laterally to a second location for the application of pressure thereto. U.S. Pat. No. 3,483,582 to Morgan also vaguely refers to an alternative arrangement wherein a portion of the disclosed structure is replaced by the pressure members of a sole attaching press.
While a number of less complex devices have been proposed, the ones known to applicant are generally capable of applying only relatively low levels of bonding pressure to a shoe. Devices of this type are disclosed in the following U.S. patents: Butterfield, U.S. Pat. No. 627,840; Myers U.S. Pat. No. 2,129,437; Johnson U.S. Pat. No. 2,162,554; Amico U.S. Pat. No. 2,285,398; Knowlton U.S. Pat No. 2,386,902; Chandler et al. U.S. Pat. No. 3,483,581; and Carr U.S. Pat. No. 3,512,197. Aside from the Butterfield and Carr patents, each of the disclosed devices is manually operated. However, the manual operating mechanisms of the devices are capable of generating only relatively low pressures urging a shoe sole against a shoe. The Myers and Knowlton devices apply pressure through simple toggle assemblies, while the Johnson and Amico devices use simple direct acting foot operated levers.
Therefore, it is desirable to provide a machine which is inexpensive and can be easily operated by an unskilled worker to securely fasten a wear portion to the underside of a shoe.